The prior art is replete with improvements to the safe handling of quick release type pneumatic couplings. They consist of a socket member or female member and a nipple or male member. The female has a spring-loaded valve normally seated in the off position which is unseated to the on position by the nipple when connected. As has been pointed out elsewhere in the prior art, couplings of conventional type such as, by way of example, those derived from the MIL Spec 4109F, suffer from safety hazards when connecting and disconnecting the coupler. Since the nipple and socket members being joined are energized by the pressurized medium being transported, it is a dangerous possibility that these members may separate in an uncontrolled and radical manner during connection or disconnection. Improvements in this art provide various locking means and pressure release means to present such explosive separation.
U.S. Pat. No. 4,366,945 to A. Blauenstein discloses a hose coupling with double lock wherein a pair of cylindrical pins provide one lock and ball-shaped locking elements provide another lock with release effected by a sliding movement of a sleeve in one direction which is arrested in its extended position by a spring loaded latch element and subsequent return in the opposite direction to the original position of the sleeve. This construction is very complex and requires many elements constructed in a complex manner.
Netherlands Patent 109393 dated Sep. 15, 1964 discloses pairs of ball bearings which appear to be operated to successive unlocking positions by shifting a sleeve in one direction and returning it to its original position.
Other pertinent art includes U.S. Pat. Nos. 2,722,399, 2,795,438, 2,905,485, 3,574,359, 3,826,523, 3,858,910, 4,060,219, 4,253,683, 4,350,321, 4,366,945, 4,413,846, 4,483,510, 4,546,956 and 4,552,333, Netherlands Patent 109393 and German Patent 2,304,796, and German published application 2,304,795, dated Aug. 8, 1974.